Over the course of its three-year digital growth binge, Microsoft’s branded properties and networks have piled up into a sometimes confusing sprawl. To limit the confusion, Microsoft is finally about to integrate those offerings into a single ad network unit in the U.S.

The combined offering, called Microsoft Media Network, will let advertisers dip into any of the company’s media properties without dealing with different contacts. In the past, agency planners had different contacts depending on whether they were buying from Drive PM, MSN, or partner sites like Facebook. And even when they did consolidate their buys across properties, marketers often received separate invoices.

“There needs to be a single quarterback,” said Scott Howe, Microsoft’s corporate vice president, advertiser and publisher solutions. “Our belief has always been the best results for advertisers will be when they have the ability to buy real granular segments but at massive scale.” He said the integrated offering will make it easier to do that.

The Microsoft Media Network will offer inventory spanning the four platforms where Microsoft represents ads: PC, mobile, gaming and digital TV. The full list of network offerings includes owned and operated properties such as MSN, Windows Live, Office Live and XBOX Live; partner sites like Facebook, Viacom, CNBC, Dow Jones; and the performance-based ad network offerings formerly known as Drive PM and Microsoft Direct Response.

The roll-out will not come as a big surprise to Microsoft’s regular customers, many of whom have already been notified of the changes. Nor does the sales integration stop with the company’s digital media products. All Microsoft sales, online and off, now sit together so as to boost efficiency and cross-selling.

“By having our salespeople use a common CRM system, often times going out together in pitches, we’re starting to tap into some of those opportunities,” said Howe. “It’s particularly true for major agencies, major publishers who might be looking for a full soup-to-nuts solution.”

There may be a risk for Microsoft in disrupting some direct sales positions, in cases where agencies had functional relationships with an individual at one or another of the company’s ad networks. Howe argues the drawback of eliminating some human relationships is outweighed by the value generated for clients in simplifying the buying process. He said doing so could help facilitate creative renaissance of the sort some leaders in the digital media sector are calling for.

“If we can eliminate the friction, it frees up more time for them to be creative,” he said of agencies.

Already launched in the U.K. and throughout Europe, Middle East, and Asia, the new branding and selling structure will hit the U.S. on March 1. After the integration here, Microsoft will launch the media network in Australia and Mexico. The company’s goal is to offer the Microsoft media network in more than 30 countries one year from now.

Howe is expected to present some details of the Microsoft Media Network in an address later today at the Interactive Advertising Bureau’s annual meeting being held in Orlando.

During the speech, Howe also plans to discuss a new collaboration with several large online publishers. Digital media firms including IAC, Dow Jones Online, The New York Times Co., Time Inc., and Viacom will contribute to the development of Microsoft’s PubCenter platform. PubCenter is designed to be an overarching solution for site-owners, and will combine its Atlas ad management products andRapt yield management solution, possibly along with other offerings such as site hosting and back office software.

An earlier version of this story stated Microsoft Media Network will include inventory from in-game ad network Massive. It will not, at least initially. The company hopes to integrate in-game inventory with time.